Electrically powered drive systems are among the oldest drive systems for vehicles. Electric vehicles first came into existence in the early-19th century, when electricity was among the preferred methods for automobile propulsion, providing a level of comfort and ease of operation that could not be achieved by the gasoline cars of the time. In time the internal combustion engine came to replace electric motors for vehicle drive systems.
Electrically powered vehicles utilize electric motors, generally, are powered by either an alternating current (AC) or a direct current (DC) power source and do not directly utilize gasoline or diesel fuels.
One requirement of electric motors is the need for an energy storage system to provide continuous power to the motors. One solution has been to use one or more batteries to power the electric motors. These batteries may store either chemical energy or kinetic energy.
Chemical batteries have to be periodically or continuously recharged in order to fully power the electric vehicle. Current batteries also only have a limited number of times in which they may be recharged. Once a battery can no longer be recharged, it must be replaced.
A popular type of potential energy battery is a flywheel. A flywheel, properly maintained, has an almost unlimited lifespan, which is not dependent upon the number of charge and discharge cycles. Furthermore, flywheels have a fast recharge time as compared to batteries. A large chemical battery may take several hours to recharge, while a flywheel may take minutes.
While present systems for driving electric powered vehicles do currently work, they have several problems. One such problem is that most electric vehicles are driven by a single electric motor. A single electric motor fails to provide sufficient power to satisfy most consumers. Most electric vehicles have a fairly slow acceleration rate when the driver presses on the acceleration pedal. Another problem is that much of the kinetic energy of the moving vehicle is wasted and therefore lost to reuse by the drive motors.
Therefore, there is still a continuing need for improved electrical drive systems for vehicles.